The present invention relates to a device for the preparation of frothed milk for cappuccino (coffee-milk beverage) which has a steam pipe connected to a superheated steam generator of a coffee or espresso maker with superheated steam flowing through the steam pipe during operation and with the superheated steam leaving the steam pipe via an outlet configuration while being mixed with air and, as needed, with milk.
Numerous embodiments of such devices are known in the prior art. Common to many of the known embodiments is the feature that the mix leaves the steam pipe in an axial direction through a single outlet. This, however, bears the risk that milk in the immediate area around the outlet nozzle becomes overheated when the lower end of the steam pipe plunges into a container filled with milk. If, in the preparation of cappuccino, milk is heated almost up its boiling point, the milk can no longer produce frothed milk of the quality required for cappuccino.
An example of the above prior art includes German Offenlegungsschrift 3,942,713 (published nonexamined application), European Offenlegungsschrift 0,472,727 (published nonexamined application), and the yet to be published European patent application 93 108 838.69 of Applicant (corresponding to U.S. patent application Ser. No. 08/082,468 to Mahlich, now U.S. Pat. No. 5,335,588).
European Patent 0,555,766.A1 to Moulinex discloses a device for preparation of frothed milk that includes a radial outlet. However, the construction is very expensive. In particular, a separate part must be provided which is disposed between the steam pipe and an outer pipe, and which has a very complicated shape. Bores must be cut into this configuration to form the flow channels and nozzles. Moreover, the outer pipe must be disposed on the underside and at a distance from an intermediate piece to form the radial flow channels. Two further preferred embodiments are disclosed in this document in which the steam/air mixture discharges through a radial outlet into a pipe piece having an axial outlet which is intended to prevent spraying of the mixture.
French Application 2,638,083 by Fregnan discloses a device for preparing cappuccino which has a radial outlet that discharges into a chamber having an axial outlet. Also, in this case Laval nozzles, which are complicated to produce, are used.